The present invention concerns an apparatus for visually displaying information and, in particular, an apparatus for displaying information in magnified form in a predetermined timed sequence to assist persons having vision deficiencies.
Devices for magnifying visual information are very useful in numerous circumstances. One use for such a device is for visually impaired persons. Most persons who are legally blind have some amount of usable vision. Such persons cannot easily read and write. Various devices have been provided for assisting those with lower residual vision These devices include large print matter such as books, periodicals, playing cards and musical scores. Also included are high intensity illuminators, broad-tipped marking pens with writing guides, specialized audio tapes, and magnifiers.
Another use is where there is a requirement that a number of people see the same information at the same time. In such a case, the vision impairment is that the person cannot physically be close enough to the material and a magnified visual display is desirable. Another use is when a speaker does not want to appear to be reading material. A magnified display can be placed a distance in front of the speaker which allows the speaker to appear to be looking at the audience at all times.
In certain instances, it is desirable for the printed material to be displayed in a predetermined time sequence. Typical examples are speeches and musical scores. Many prior art devices have been provided, particularly in the area of music. For example, U.S. Pat. No. 2,483,570 discloses a music timing apparatus. An opaque material strip having musical staffs and notes formed thereon is moved past a light source. Each note is indicated with an aperture wherein the light becomes visible through the aperture as the material strip is moved. The movement of the strip is timed in relation to musical time.
U.S. Pat. No. 3,991,648 discloses a music teaching device having two aligned rows of lamp indicators providing a coordinated physical representation of an associated aligned sheet of music. The lamps of the first row of indicators are illuminated consecutively, each lamp remaining lit for the same time period to provide a visual metronome. The lamps of the second row of indicators are illuminated in selected groups coordinated with the metronome lamps and each group remains lit for the time period corresponding to the notes on the sheet of music. The device includes a scanner, which provides trigger impulses producing substained, rather than flashing illumination of individual lamps and groups of lamps; and a switching system, which ties individual lamps of the second row together for simultaneous indication. In addition, an audio metronome provides a choice of sounds for accent purposes and an audio note section provides a choice of pitch for both individual notes and chords.
U.S. Pat. No. 4,097,135 shows an audio-visual apparatus which includes a projection screen having indicia formed thereon representative of a note play marker, means for successively projecting onto the screen adjacent the note play marker a plurality of visual images of a musical composition recorded on a film strip, means for providing a sound recording of the musical composition and control means for relating the projection of visual images with the playing of the sound recording.
U.S. Pat. No. 3,577,824 discloses a music teaching machine which produces small lighted areas on a screen having musical notations in response to depressions of the keys of an associated musical instrument. The lights are color coded and physically positioned to indicate the sets of notes constituting major thirds and minor thirds. A movie picture projector, lens system and a mirror are arranged to project notes, to be played, on the same screen.
U.S. Pat. No. 4,331,062 discloses an apparatus for visually displaying music notes including a front panel with a grand staff printed thereon and individual light indicators for the various notes of a keyboard.
U.S. Pat. No. 3,887,275 discloses an automatic slide music stand having a pair of supporting legs which are spaced apart to allow one or both legs of a musician to be positioned therebetween when the musician is seated. An inclined opaque projection screen is inclined toward the musician for viewing each sheet of a musical score individually on the screen utilizing one sheet of music per slide in a slide projector mounted behind the screen. On-off, brightness, and projection time controls are provided.
Musical training for low vision individuals traditionally has been largely accomplished without the use of the standard musical score. If printed material were utilized, significant enlargements were then required. Often these enlargements were created by hand or expensive photo-enlarging copying machines with a quality that was less than satisfactory. Although large print music is sufficient for those individuals with slight amounts of vision loss, there are many individuals who cannot benefit by simply doubling or trebling the size of standard music.
Alternative methods of instruction often have resulted in differing the process of musical instruction, which generally meant the discontinuation of the use of printed music altogether. This form of instruction is quite often less than satisfactory, depending on the qualifications of the teacher, and the abilities and memory of the student. Other considerations reducing the effectiveness of teaching without the benefit of music are psychology related, since those who are visually impaired, more often than not, thrive on the opportunity for full participation. Methods of instruction for which a musical score could not be utilized often included rhythm dictations, studies in musical form, training in styles of accompaniment, and so called "playing by ear". Instructional techniques such as these are, indeed, fundamental, however they are not designed for the majority of students with low vision, since most learners progress more naturally in their studies aided by the use of printed music.
Optical aids which are intended to aid persons who suffer from vision loss include the magnifying glass, the monocle and spectacles. However such lenses are generally limited to magnifications of twelve or less.
Optical aids providing greater magnifications include the free-standing magnifier, which can be situated between the music stand or piano and the user. If additional magnification is required, a hand magnifier can be used in conjunction with a stand magnifier. However, stand magnifiers can only be helpful for a limited group of individuals with vision loss, since only limited powers of magnification can be achieved.
Another problem associated with any purely optical aid is that of maintaining correct focal distance. Any movement by the user which alters this focal distance will tremendously effect the clarity of the image. Among other considerations are the limited scope of visual field provided by most magnifying lenses and the requirements of adequate, glare-free illumination.
Other modern developments encompass a variety of electronic magnifiers and illuminators such as a closed circuit television monitor, often coupled with a large display computer processor, allowing for tremendous flexibility in the projected information, as well as providing magnification many times that of large print, commonly sixty times or more. Systems of this type are extremely beneficial to those with vision loss; however, due to restraints in terms of costs, ease of operation, availability of programming materials, physical size, as well as other considerations, such devices are unfortunately seldom practical.
Other problems associated with vision impairment are contrast and color. Light is a component of the electromagnetic spectrum and the visible region for an assumed standard observer at normal levels of illumination extends from about 4300 Angstroms to about 6900 Angstroms in wavelength. One Angstrom is 10.sup.-10 meter. Since the eye sensitivity curve approaches the wavelength axis asymptotically at both the violet (short wavelength) and red (long wavelength) ends, the limits of the visible region are usually defined at 1% of the maximum sensitivity value. The maximum value occurs in the center of the visible region at about 5550A producing a sensation of yellow-green. Typically, printed music is black on a white background and, when projected on a viewing screen, provides excellent contrast. However, where the viewer has reduced sensitivity, contrast can be increased by providing a color for the background and/or the musical notation. For example, the eye is more sensitive to blue than to green and more sensitive to green than to red.